• From: Detroit
  • Registered: 2006-06-02
  • Posts: 5,807

Topic: First preamp tube in line

hi all... i want to ask about premap tubes.

if you have 3 or 5 preamp tubes in line... I understand the first one has to be the quietest.
I have JJ and TUNG-SOL preamp tubes in my Rivera, and I had to rearrange them all so when you tap on them with your finger, the first one in line is quiet.

My amp is way too high gain for me, and I'm thinking about getting some low gain preamp tubes,,, or maybe just one and hope that it's quieter than all my others.

thoughts?

- Nic from Detroit... posting on JB's Forum since 6-2-2006
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  • Registered: 2011-02-08
  • Posts: 18

Re: First preamp tube in line

NPB_EST.1979 wrote:

hi all... i want to ask about premap tubes.

if you have 3 or 5 preamp tubes in line... I understand the first one has to be the quietest.
I have JJ and TUNG-SOL preamp tubes in my Rivera, and I had to rearrange them all so when you tap on them with your finger, the first one in line is quiet.

My amp is way too high gain for me, and I'm thinking about getting some low gain preamp tubes,,, or maybe just one and hope that it's quieter than all my others.

thoughts?

What do you mean by 1st one? V1 the furthest from the output tubes?
I do not know too much about the Rivera's but V1 is typically the clean channel driver.
I would avoid tapping on tubes as that can cause drifting I believe.
Try to find out which tube is running the OD/gain section and it could possibly be replaced with 12au7 instead of 12ax7 which is a lower gain replacement tube.
All said, I dont even know which Rivera you speak of, does it have 3 or 5 pre's?
Another suggestion: I go through Doug's tubes and maybe you can contact him or another tube company and get suggestions based on your amp model.

Hope that helps a little
Todd

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  • From: North Carolina
  • Registered: 2008-10-26
  • Posts: 2,926

Re: First preamp tube in line

The only thing I know about Preamps is V1 colors the rest of the preamp.  So if your wanting to cut the distortion 12Ax7 might not be doing it for you, so use a 12AT7 should give you more headroom.  Also people think they have to run every tube in the preamp NOS expensive but thats not true, V1 like I said colors the preamp so if you put the expensive tube in there like a Mallard or something the other tube can be stock because all they do is power the rest of the preamp they don't add color.  Got that out of Vintage Guitar Mag 3 years ago.  Doesn't work the same for output tubes though.

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